Cupric, nickelous and argentous ion-selective chelating resins

ABSTRACT

A polymer-ligand comprising a high molecular weight water insoluble polymer containing certain covalently bonded ligand moieties is capable of selectively chelating cupric and/or argentous ions from aqueous solutions containing them and other metal ions. Exemplary is polystyrene containing the moiety   WHICH IS BOUND TO THE POLYMER CHAIN THROUGH THE OXYGEN ATOM.

United States Patent 1 Melby 1 1 CUPRIC, NICKELOUS AND ARGENTOUSION-SELECTIVE CHELATING RESINS [75] Inventor: Lester Russell Melby,Wilmington.

Del.

[73] Assignee: E. I. du Pont de Nemours and Company, Wilmington, Del.

22 Filed: Mar. 27, 1973 21 Appl. No.: 345,314

[52] US. Cl 423/24, 75/101 BE, 260/22 R, 423/139 [51] Int. Cl. B0ld15/04, C08f 27/08 [58] Field of Search 260/22 R; 423/24; 75/101 BE 1 56]References Cited UNITED STATES PATENTS 3,037,945 6/1962 Morris 260/213,337,480 8/1967 Small 1 260/22 3.473.921 10/1969 Schmuckler 75/118OTHER PUBLICATIONS Goodwin et al.. J. Am. Chem. Soc, 82, 5013-5023 11960).

1 1 Mar. 25, 1975 Primary [:Ituminw-Melvin Goldstein [57] ABSTRACTPIN-CH2 which is bound to the polymer chain through the oxygen atom.

16 Claims. N0 Drawings BACKGROUND OF THE INVENTION 1. Field of theInvention This invention provides insoluble chelating polymers whichselectively bind certain metal ions in the presence of other metal ionsand thus are suitable for obtaining purified concentrates from which thefree metal may be recovered.

More specifically this invention provides insoluble chelating polymersystems which (1) selectively bind cupric and argentous ions in thepresence of ferric, ferrous, cobaltous and nickelous ions, or (2)selectively bind cupric, argentous, and nickelous ions in the presenceof ferric, ferrous and cobaltous ions. These systems are effective inobtaining purified concentrates for recovery of copper and/or silver, orcopper, nickel and/or silver from low grade mine liquors.

2. Prior Art Mine liquors from spent copper mines of the sulfide oretype contain low concentrations of cupric (Cu**) and ferric (Fe ions,the liquors of which are acidic (pH 1-3 Conventionally, purified cupricion solutions of commercial value are obtained from such mine liquors byliquid-liquid extraction with organo-soluble chelating agents (ligands)which are more or less selective for Cu in the presence of Fe at low pH.The organic extract containing organo-soluble copper chelate is thenback extracted (stripped) with strong mineral acid, e.g., sulfuric acid,the acidic extract is then electrolyzed to obtain copper metal and theregenerated organic solvent-ligand solution is recycled to the liquorextraction step. High selectivity for Cu over Fe" is necessary becausethe presence of excessive amounts of Fe interferes with the electrolyticrecovery (electro-winning) process.

It is well known that a solid-liquid extraction system affords severalinherent mechanical advantages over liquid-liquid extraction systemssuch as elimination or simplification of such steps as mixing, settling,separation and recycling of solvents.

H. A. Goodwin and F. Lions, J. Amer. Chem. Soc. 82, 5013 (l960) discussthe preparation of various metal chelating compounds. They show that2,2'-bis- (2-pyridylmethylamino)biphenyl is able to chelate copper ions.No mention is made ofa polymer containing chelating moieties nor thechelating selectivity as to copper and silver.

SUMMARY OF THE INVENTION The invention comprises a high molecular weightwater insoluble polymer containing about 0.3 to about 2 millimoles ofacovalently bonded ligand per gram of polymer, the ligand having theformula 29 (line Y y' wherein R is H or alkyl of 1-3 carbon atoms;

2 X and X independently are NH, O, or S;

Y is or t;

and Y' is I R in which 2 IS O S 2)"1 Z)H NH, or NH(CH where n l to 10; Qis N; and

Q is NH, O, or S;

with the proviso that at least three of X, X, Q and Q are nitrogen;

the said ligand being attached to the methylene carbon by the indicatedvalence bond and being attached to the polymer through the Z group.

Preferred ligands are those where the indicated valence bond is in theortho position relative to the ring nitrogen or the Q or O atom. Alsopreferred are those ligands in which each of X and X is a nitrogen atom.

The polymer component of the invention has a high molecular weight, isinsoluble in water and is stable to sulfuric acid of 1-25%concentration. It is preferred that the polymer also be insoluble in theorganic solvents which may be used in the process of binding the polymerto the ligands. The polymer can be in any of various forms since it actsmerely as a base or support for the chelating ligands. Thus the polymermay be used as beads or other small particles having a large surfacearea or may be in the form of a continuous belt as described below.

Useful polymers include polyvinyl chloride, polyvinylidene chloride, andchloro-, bromo-, or iodomethylated polystyrene, etc. The preferredpolymer used in making the polymer-ligand is chloromethylatedpolystyrene. Typically, such a polymer is made insoluble bycross-linking styrene with divinylbenzene. The degree of cross-linkingmay vary from 0.58% by weight of divinylbenzene and the polymers mayexist as beads or pulverized solid. Such polymers are prepared andchloromethylated by any of a variety of means known and described in theprior art, as for example, U.S. Pat. Nos. 2,614,099 and 2,629,710.

The polymer may be prepared also by radiation grafting styrene to aninert polymer such as polyethylene or polypropylene in the form of aparticulate solid or continuous material, such as woven fabric, bundledfibers, or as spunbonded felted material such as Tyvek, a spun bondedpolyolefln. The continuous materials may be in the form of an endlessbelt. Such styrene-grafted materials are then chloromethylated prior toligand attachment.

The ligand component of the invention is a biphenyl compound of thegeneral formula above having a hydroxy, thiol, thioloalkyl (HS(CHhydroxyalkyl (HO(CH amino (NH or aminoalkyl (NH -(CH and the like if theligand is to be attached to a preformed polymer by nucleophilicsubstitution. Such groups can be on any one of the four aromatic nucleicomprising the essential ligand structure.

3 4 The ligands are reacted with a polymer having reactive layers wereclear. The ether was separated. washed groups such as chlorine, bromine,or iodine, etc., with 100 ml of water, dried briefly with sodium sulfatethrough a condensation reaction to split out halogen and evaporated to50 ml on a steam bath. It was cooled acid, etc. Where the ligandcontains a polymerizable to room temperature and magnetically stirredovervinyl group, it may be connected to the polymer by a 5 night.N-(2-pyridylmethyl)-2,2'-diaminophenyl (A) copolymerization reaction. Asan illustration, a ligand separated as a finely divided crystallinewhite product.

containing 21 OH group can be attached by condensa- The mixture wasstored at lOC. overnight and the tion with the chloromethylated polymerin the presence product was collected and washed with a small amount ofa strong base such as an alkali metal alkoxide, alkali of cold ether;the yield was 912 g (67%), mp 85-95(.

metal hydroxide or carbonate, quaternary ammonium Another 2.0 g wasobtained from the concentrated hydroxide, or a tertiary amine in aninert solvent, such mother liquor (total yield, 82%). This material wasas dimethylformamide, dimethylacetamide, dimethylthen recrystallizedfrom benzenehexane giving a matesulfoxide, hexamethylphosphoramide ordioxane at rial having a melting point of 93-94C.

temperatures ranging from ambient to about 100C. in

the presence or absence of one molar equivalent of wa- Anal. Calcd, forC H N, (mol. Wt. 275.3 C, 78.5; H, 6.2; N, l5.3 SPECIFIC EMBODIMENTS OFTHE INVENTION Found: c, 78.2; H. 6.3; N, 15.0

The following are illustrative examples of the invention in which allparts are by weight unless stated other- The reaction produces aninterim monoimine which wise. is reduced to form the desired startingmaterial. The re- EXAMPLE 1 action is carried out near or in thepresence ofa solvent such as an alkanol of 1-4 carbon atoms (methanol,eth- Ligand anol propanol etc benzene or alkyl benzene (tolu-N-(p-Hydroxyphenylmethyl)-N-(2-pyr1dylmethyl)- ene Xylene etc)'dlammoblphenylu) The reaction temperature is usually maintained at A.The precursor for this ligand is prepared as fol- 8090C. or at theboiling point of the solvent chosen.

lows: If no solvent is employed, a temperature of 80l00C.

To a stirred, refluxing solution of 9.2 g (50 moles) of 40 is preferred.In any case, the amine aldehyde mixture 2,2-diaminobiphenyl in 200 ml ofethanol was added must be in a liquid state. The reaction may occurspondropwise during 2 hours a solution of 5.3 g moles) n usly when hereactants are mixed- Of py nee y (redislilled. P 15 Reduction of themonoimine to the corresponding in ml of ethanol. When addition wascomplete, the amine is accomplished by using any of a number ofremixture was refluxed for an additional 30 minutes and 45 ducing agentssuch as sodium borohydride in lower alwas then cooled to roomtemperature. Three grams of kanols, sodium metal in lower alkanols,lithium alumisodium borohydride was added and the solution was numhydride in ether or tetrahydrofuran, or catalytistirred overnight (16-20hours). Another 3 g of sodium cally with hydrogen gas at atmospheric orsuperatmosborohydride was added and stirring continued for 24 phericpressure and temperatures from 20C. to 100C. hours more. The solutionwas transferred to a large Er- 50 in inert Solvents Over typicalhydrogenation Catalysts lenmeyer flask and boiled to virtual dryness ona steam Such as nickel, platinum of palladiumbath. Approximately 500 mlof water and 300 ml of B. Precursor A is used in the following reactionto ether were added and the mixture was stirred until both Produceligand -H O mono- Q@ 1 [imine H H-CH CH -NH 2 2 cao 2 Solutions of 8.0 g(29 mmoles) of N-(2-pyridylmethyl)-2,2-diaminobiphenyl (A) and 3.54 gmmoles) of p-hydroxybenzaldehyde, each in 40 ml of ethanol were mixedand boiled gently for 0.5 hour, cooled to room temperature and made upto 100 ml volume with fresh ethanol. Two grams of sodium borohydride wasadded and the mixture stirred at room tem perature for 5 hours. Another2 g of sodium borohydride was added and stirred for an additional 16hours. The solution was boiled to dryness on a steam bath and theresidue treated with 400 ml of water. A thick syrup separated and thewater was decanted. The syrup was washed by decantation with water andwas taken up in 200 ml of ether. The ether solution was dried withsodium sulfate, filtered, and concentrated to 50 ml volume. On standingat room temperature overnight, the solution deposited about 5 g ofN-(phydroxyphenylmethyl )-N 2-pyridylmethyl )-2,2 diaminobiphenyl l) asa white crystalline solid. It was recrystallized from 98% alcohol, thesolution was chilled at 1 5 to 20C. overnight and the crystals of ligandmonohydrate were collected and dried in a stream of moist air, mp, l 16l18C.

This monohydrate was heated at 80C. in a vacuum crystals. The iminecompound was recrystallized from ethanol, mp, 148150C. Recrystallizedimine (2.4 g) and 1 g of sodium borohydride in 280 ml of ethanol wasstirred at room temperature for 16 hours and then evaporated to dryness.The residue was taken up in a mixture of 300 ml of water and 150 ml ofether and the mixture was stirred until clear. The ether layer wasseparated, dried over anhydrous sodium sulfate and con centrated to 20ml volume, then chilled to obtain 0.9 g ofN-(3-hydroxy-2-pyridylmethyl)-N-(2- pyridylmethyl)-2,2 -diaminobiphenyl(2) as white crystals. The water layer was buffered to pH 8 with sodiumbicarbonate to obtain a second crop, weighing 0.5 g. The combined cropswere recrystallized from 66% aqueous ethanol to obtain white crystals,mp, 181183C.

75.4; H. 7. Found: C, 75.9; H, 6.0;

Ligands l and 2 are presently preferred. Their donor to obtain theanhydrous form, mp, 132135C. atoms, which are responsible forcoordinating the metal ion in metal scavenging processes, are allnitrogen atoms. In tetradentate ligand 2, one of the donor Anal. Calcd.for C H N O; C, 78.7; H, 6.0; N, 11.0. atoms may be replaced by anoxygen or sulfur atom. ln

Found: (178-7; all cases, two of the donor atoms must be attacheddirectly to the 2- and 2- positions of the biphenyl nu- EXAMPLE 2 cleus.Ligand 1 is selective for cuprous and argentous ions in the presence offerric, ferrous, cobaltous and Ligand I nickelous ions and the ligand 2moiety is selective for Y Y 'RYQ m l '(z'pyndylmethyn cuprous, argentousand nickelous ions in the presence 2,2 'dlammoblphenyl (2) of ferric,ferrous and cobaltous ions.

0H H O mono- H 1., H CH mine a;

N CHO 5 HO ca NH Nit-0H Commercially available3-hydroxy-2-hydroxymethylpyridine hydrochloride was converted to thefree base with sodium bicarbonate. The base was oxidized to the aldehydewith manganese dioxide in refluxing benzene in a manner known to theart. The aldehyde hydrochloride was isolated by passing dry l-lCl intothe filtered benzene solution.

A mixture of4.3 g 15.5 mmoles) ofN-(Z-pyridylmethy1)-2,2'-diaminobiphenyl (A) and 2.5 g (15.5 mmoles) ofthe above hydroxypyridine aldehyde hydrochloride in 100 ml of ethanolwas boiled gently on steam for 15 minutes and the solution was thenchilled at -15 to 20C for 2 days to obtain 1.7 g of yellow EXAMPLE 3 no.c NH-LHQ A solution of 2.75 g of N-(2-pyridylmethyl)-2,2-diaminobiphenyl (A) and 1.22 g of salicylaldehyde in 25 ml. ofethanolwas vigorously boiled on a steam bath until the volume was .10ml. It was chilled at 20C. overnight to obtain the crude orange-yellowcrystalline imine 3; yield 3.4g (90%), mp 106-l10C.

For analysis a small portion was recrystallized from ethanol, mp108112C.

Anal. Caled for C,,,H, N O(MW 379.4): C. Found: C,

NMR(CDC1;,)8 8.42 (S, 1,=CH), 8.2-8.39 (m, l, pyridine a), 6.4-7.4 (m,15 aromatic and pyridine B, 7). 4.35 (S, 3, -CH and NH).

EXAMPLE 4 N-( 2-1-lydroxybenzyl )-N 2-pyridylmethyl)-2,2 diaminobiphenyl(4) Anal. Calcd for H- N (MW 381.4): C. 78.8; H, 6.1;N, 110 Found: C,78.9; H, 6.2; N. 11 0 EXAMPLE N-( 3-Hydroxybenzylidene )-N2-pyridylmethyl )-2,2 diaminobiphenyl) (5) The reaction of3-hydroxybenzaldeh yde and pyridylmethyldiaminobiphenyl was carried outas described 8 for ligand 4, the 2-hydroxy isomer, to obtain the imine 5as slightly yellow matted needles; yield 2.7 g. mp 6972C. The air-driedproduct was the hemlalcohulate.

Anal. Calcd for C ,,H ,N; ().1/2C H OH (MW 402.5):

77.5; H, 6.9; N, 10.4. Found: C, 77.2; H, 6.3; N, 10.4.

EXAMPLE 6 N-( 3-Hydr0xybenzyl )-N 2-pyridylmethyl )-2,2 diaminobiphenyl(6) The 3-hydroxy imine 5 was reduced as described for the 2-hydroxycompound. The crude mixture was evaporated to dryness, the residuetriturated with water and solid 6 collected. It was recrystallized fromethanol 10 ml/g) to obtain purified product in 66% yield, mp l48-150C.

Anal. Calcd for C H N O (MW 381 .8, H, 6.1 Found; C, 78.6; H, 6.3;

EXAMPLE 7 A. N-( 6-Methyl-2-pyridylmethyl )-2,2 '-diaminobiphenyl Thereaction of 2,2-diaminobiphenyl with one molar equivalent of6-methylpyridine-2-aldehyde and reduction of the intermediate imine withsodium borohydride was carried out as described for the unmethylatedanalog (Example 1). Since the product did not crystallize. it was usedas a crude sirup obtained by evaporating the ether extract to dryness.

N-( 3-Hydroxy-2-pyridylmethylene )-N 6-methyl-2-pyridylmethyl)-2,2-diaminobiphenyl (8) To a solution of 22 g of compound7 in 100 ml of ethanol was added a separate solution of 6.0 g of 3-hydroxypyridine 2-aldehyde hydrochloride in 100 ml of ethanol and 5.25ml of triethylamine was added immediately. The mixture was gently boiledon a steam bath for 5 min. then stored overnight at C. The yellowcrystalline product 8 was collected on a filter, washed with a smallamount of ethanol, then with water, and air dried. The crude yield was 11.8 g (80% based on aldehyde) and the mp l40-l42C. It was recrystallizedfrom ethanol (30 ml/g, Darco) to obtain 8.5 g mp 148-151C.

Anal. Calcd for C l-l N O (MW 394.5):

.1- H, 5.6; N] Found: C, 76.4; H, 5.7; N, l

NMR (CDCl;,) 8 12.5 (broad, OH), 8.74 (S, l==Cl-l-), 80-815 (m, 1,pyridine a), 6.5-7.5 (m, 13, aromatic and pyridine B, y), 4.7 (broad.NH), 4.2-4.5

(m, 2, -CH 2.35 s, 3, -CH

EXAMPLE 8 N-( 3Hydroxy-Z-pyridylmethyl )-N 6-methyl-2-pyridylmethyl)-2,2diaminobiphenyl (9) H0 /CH2-NH NH-CH EXAMPLE 9 A.3-Hydroxy-6-methylpyridine-2-aldehyde Hydrochloride (10) lnto a 2-1,one-neck flask was placed 1 liter of benzene and 20 g of commerciallyavailable 2- hydroxymethyl-3-hydroxy-6-methyl pyridine. With continuousmagnetic stirring g of finely-divided, activated manganese dioxide(Shepherd Chemical Co.) was added in portions to ensure uniformsuspension. The flask was equipped with a Soxhlet extractor head with acup capacity of about 75 ml, the cup containing 20 g of 4 A molecularsieves. The mixture was heated under reflux for 5 hrs., cooled to roomtemperature, the benzene suspension filtered and the filter cake washedwith 200 ml of benzene. The filtrate was saturated with dry hydrogenchloride, the precipitated hydrochloride 1O collected, washed withbenzene and dried. It was vacuum sublimed at l40C., 1-2 mm pressure;yields 12-16 g (50-65%); mp 2l5-217C. (dec).

Anal. Calcd for C H CINO (MW) 173.6): C, 48.4; H. 4. N, 8.

Found: C, 48.]; H, 4.

B. N-( 3-Hydroxy-6-methyl-2-pyridylmethylene )-N 2-pyridylmethyl)2,2-diaminobiphenyl l 1) HO CH=N NH- CH2 Anal. Calcd for CH MO (MW 394.5):

C, 76.1; H, 5.6; N, 14.2. Found: C, 76.5; H, 5.7; N, 14.0.

NMR (CDC1 6 12.2 (-OH), 8.80 (S, l =CH-) 8.3-8.5 (m, l, pyridine a),6.5-7.5 (m, 13, aromatic and pyridine ,8, 7), 4.40 (broad S, 3, NH andCH 2.42 (S, 3, CH

EXAMPLE l N-(3-Hydroxy-6-methy1-2-pyridylmethyl)-N'-(2-pyridy1methyl)-2,2-diaminobiphenyl 12) HO CH Anal. Calcd for C -,H N O(MW 396.5):

C, 75.7; H, 6.1; N, 14.1. Found: C, 75.7; H, 6.1; N, 14.0.

EXAMPLE 1 l A. N-( 2-Pyridy1methy1)-2,2-diamino-6,6'- dimethylbiphenyl(13) H3 CH3 2-1odo-3-nitroto1uene was prepared by a known method. Thecrude product was recrystallized from hexane (10 mI/g, Darco) to obtain80-85% yields of purified material, mp 62-64C. Coupling of the iodocompound was carried out by heating a mixture of the iodo compound with50% of its weight of copper bronze (United States Bronze Powders, lnc.,Copper Bronze Natural, Copper Fine, type 44) and an equal weight of sandat l75l80 for 1 hour. Benzene extraction and recrystallization of thecrude product from ethanol gave purified 2,2'-dinitro-6,6-

dimethylbiphenyl in 70% yields, mp 106-107C. 5 Hydrogenation of thedinitro compound in ethyl acetate l0 ml/g) with Raney nickel catalystand hydrogen at 8 atm and room temperature for 4-5 hrs gave the diaminein 85% yields after recrystallization from ethanol (3m1/g), mp l34-l36C.

Reaction of 2,2-diaminc-6,6-dimethylbipheny1 with 1 mole ofpyridine-2a1dehyde followed by reduction with sodium borohydride asdescribed previously (Examples 1 and 7) gave compound 13 as a crudesirup. 15

B. N-( 3-1-lydroxy-6-methyl-2-pyridylmethylene )-N 2- pyridylmethyl)-2,2 -diamino-6,6-dimethy1bipheny1 To a solution of 9 g of sirupy 13 in50 ml of ethanol was added a solution of 5.2 g of the aldehydehydrochloride 10 in 50 ml of ethanol. Sodium methoxide (1.62 g) wasadded and the mixture was boiled gently for 30 mins then chilled at 20overnight. The crude product 14 was collected, washed with ethanol andwater and dried. The crude yield was 4.8 g (38%). It was recrystallizedfrom ethanol (5 ml/g) to recover 3.0 g (24% yield), mp 153l56C.

Anal. Calcd for C ,H,N7,O

, 6.8; Found: C, 76.7;

NMR (CDC1 6 12.9 (S, 1, OH), 8.79 (S, 1, =CH), 8.27-8.47 (m, pyridinea), 7.5-6.4 (m, 11, aromatic and pyridine {3, 'y), 4.27-4.47(m, 2, CH3.97-4.45 (In, --NH), 2.44 (s, 3, pheny- 1-CH 1.86 s, 3, phenyl-CH;,).

EXAMPLE 12 N-( 3-Hydroxy-6-methyl-2-pyridylm ethyl )-N 2-pyridy1methy1)-2,2-diamino-6,6'-dimethy1biphenyl 15) c11 CH3 CH2- -CH2 Afiltered solution of 2 g of sodium borohydride in 100 ml of ethanol wasadded to a stirred suspension of 8.2 g of imine 14 in 100 m1 of ethanol.Stirring was continued for 4 hrs and the first crop of white product 15was collected, yield 4.75 g, mp l92195C. The filtrate was evaporated todryness and the residue was slurried with water to obtain a second cropof crudesolid (3.04 g) which was recrystallized from ethanol to recover2.4 g of purified product, mp 192-195C.

A portion of the first crop was recrystallized from ethanol foranalysis, mp 194l95C.

Anal. Calcd for C ,-H ,.N,O (MW 424.5): C. 76.5; H. 6.65;

N. 13.2. Found: C. 76.5; H. 7.0; N, 13.3.

EXAMPLE 13 A. N-( 3-Hydroxy-2-pyridylmethy1ene )-N 2- pyridylmethyl)-2,2 '-diam ino-6,6 '-dimethy1biphenyl CH3 CH3 o CH=N Nit-H To 13 g ofamine 13 (Example 1 1) in 200 ml of ethano1 was added a solution of 6.9g of 3-hydroxypyridine- 2-aldehyde hydrochloride in 100 ml of ethanolfollowed immediately by 2.3 g of sodium methoxide. The mixture wasboiled on a steam bath for 30 mins., cooled to room temperature,filtered, and the filtrate concentrated to 50 ml volume. The solutionwas chilled at to C. for 2 days and the yellow crystalline product 16was collected and recrystallized from ethanol to obtain 5.2 g ofpurified material, m.p. l-l42C. For analysis a small portion was againrecrystallized.

Anal. Calcd for C H MO (MW 408.5): N. 13.7. Found: N. 13.7.

NMR(CDC]3)812.4(S,1,0H),8.99(S,1.=CH), 8.6-8.4 (m. 1. pyridine a). 8.28(I. l. J 3. pyridine a). 7.5-6.5 (m. 11. aromatic). 4.51 (.r. 1. -NH-).4.44 2. (H 2.16 (.r, 3. CH0. 1.94 (.r. 3. -(H;,).

B. N-( 3-Hydroxypyridylmethyl )-N'-(2-pyridylmethy1)-2,2'-diamino-6.6'-dimethylbiphenyl (17) H0 GH -Na N'H-CI-I Anal. Calcdfor C H MO (MW 4105): C. 76.1; H. 6.4;

N, 13.7. Found: C. 75.9; H. 6.9; N, 13.4.

EXAMPLE 14 N-( 3-Hydroxy-6-methyl-2-pyridylmethylene )-N 6-methyl-Z-pyridylmethyl)-2,2-diaminobipheny1 18) o CH N H-CH2 To asolution of l l g ofa sirupy compound 7 (Example 7) in ml of ethanol wasadded a solution of 3- hydroxy-6-methylpyridine-Z-aldehyde hydrochloride10 and 1.85 g of sodium methoxide. The mixture was heated on a steambath for 30 min., concentrated to 50 ml volume, filtered and thefiltrate chilled overnight at l0 to 20C. The yellow solid 18 wascollected, washed with water and recrystallized from ethanol to obtain5.0 g (36%) of yellow needles, mp. 59-62. Recrystallized again from EtOHthe m.p. was 64C.

Anal. (ulctl l'or .,.H ..N.() (MW 408.5): (I 72);; H. 5.9;

Found: C. 76.7; H. 6.1. N. 13.6.

NMR (CDCl;,) 5 12.2 (s, OH), 8.83 (s, =CH), 7.56.5 (m, aromatic), 4.41(broad s, CH NH). 2.46 (s, CH 2.40 (s, CH

B. N-( 3-Hydroxy-6-methyl-Z-pyridylmethyl )-N 6-methyl-2-pyridylmethyl)-2,2'-diaminobiphenyl (19) Anal. Calcd for C ,,H,,N O (MW 410.5 N, l

3.7. Found: N, 13.7.

EXAMPLE IS A. N-( 6-Methyl-2-pyridylmethyl )-2,2 diamino-6,6dimethylbiphenyl The reaction of 2,2'-diamino-6.6-dimethylhiphenyl with6-methyl-pyridine-2-aldehyde and reduction with sodium borohydride wascarried out in the way previously described (Examples 1. 7 and l l) toobtain the amine 20 as a sirup.

B. N-( 3-Hydroxy-6-methyLZ-pyridylmethyl )-N 6- methyl-2-pyridylmethyl)-2,2 -diam ino-6,6 dimethylbiphenyl Trihydrochloride (21) To a solutionof 15 g sirupy compound (20) in 50 ml of ethanol was added a solution of5.2 g of the methylhydroxypyridine aldehyde 10 in 50 ml of ethanol, and1.62 g of sodium methoxide was added. The mixture was heated on a steambath for 30 mins., filtered free of NaCl, cooled to room temperature,and stirred overnight with 2 g of sodium borohydride. The mixture wasevaporated to dryness, dissolved in 50 ml of hot 3 N HCl, treated withDarco, filtered and chilled overnight to obtain the product 21 as fine,yellowish needles, mp. 164l70C. (dec.).

N, 10.2. Found: C, 6L0; H, 6.3; N, 10.3.

Examples of operable ligands in which one of the donor nitrogen atomshas been replaced by O or S in a tetradentate ligand analogous to ligand2 are:

N- S-hydroxymethyl-Q- finyl CH methyl)-N'-(2-pyridylmethyl)- 2,2-'-diaminobiphenyl A. Polystyrene beads, 200-400 mesh, crosslinked with2% divinylbenzene, were chloromethylated according to known methods. Inthe procedure 50 g of crosslinked polystyrene beads was allowed to swellin 200 g of chloromethyl methyl ether for 1 hour at room temperature. Amixture of 7 ml of anhydrous stannic chloride in 100 ml of chloromethylmethyl ether was added and the mixture stirred and boiled under refluxfor 1 hour. The beads were collected on a filter and washed successivelywith dioxane-water, dioxane-cone.

hydrochloric acid, dioxane and finally, methanol or ethanol. Aftervacuum drying the product contained 21% chlorine.

A mixture of 2.26 g of ligand (1) in monohydrate form and 0.32 g ofsodium methoxide in 20 ml of anhydrous freshly distilleddimethylformamide (DMF) was stirred under nitrogen at room temperaturefor 10 minutes and then 1.0 g of the chloromethylated polystyrene wasadded. The mixture was stirred and heated at 8590C. for 16 hours.

The product was collected on a course frit filter and washedsuccessively with 20 ml-portions of DMF containing 10, 20, 50 and 75%water (v/v) by volume, then with 20 ml of DMF and then successively with20 mlportions of DMF containing 10, 20, 50 and 75% ethanol (v/v); then,finally, with ethanol alone. The product was vacuum-dried at 90C. for 18hours, yielding 2.25 g. Analysis: Found: N, 6.7%. 6.5%, corresponding to1.57 millimolcs of ligand per gram of polymer.

B. A two-fold scale reaction analogous to part A above was carried outto obtain 5.14 g of the product. Analysis: Found: 7.6% N, correspondingto 1.81 mmoles of ligand per gram of polymer.

C. A preparation analogous to the one described in part B above wascarried out using one molar equivalent of anhydrous ligand (1) insteadof the monohydrate. The yield was 5.23 g and the product contained 7.5%nitrogen corresponding to 1.79 mmoles ofligand per gram of polymer. Thispolymer, using the anhydrous ligand, produces a product with differenthandling and selectivity characteristics.

D. A polymer preparation analogous to that of part A above was carriedout using a 1% crosslinked chloromethylated polystyrene containing 23.4%chlorine (6.75 mmoles per gram) and appropriate molar equivalents ofligand monohydratc (1) and other reagents. The yield was 5.47 g and thepolymer contained 7.8% nitrogen. corresponding to 1.85 mmoles of ligandper gram of polymer.

N- (B-hydroxy- 2-pyr1dylmethyl) N (2- thienylmethyl) 2, 2'-diaminobiphenyl EXAMPLE 17 1% crosslinked Polystyrene with HydratedLigand 2 A. The reaction between 2.0 g of 1% crosslinkedchloromethylated polystyrene, 5.15 g ofligand (2), 243

l of water and 0.75 g of sodium methoxide in 50 m1 of DMF was carriedout as described in Example 16, part D above.

Product yield was 5.35 g and the nitrogen content was 10.4%corresponding to 1.86 mmoles ofligand per gram of polymer.

B. The reaction of part A immediately above was re peated but withoutadded water. The polymer yield was 5.63 g and the nitrogen content was10.8% corresponding to 1.93 mmoles of ligand per gram of polymer.

EXAMPLE 18 Chloromethylated Polystyrene, 1% Crosslinked, 200-400 MeshBeads A commercial sample* of 1% crosslinked polystyrene, 200-400 meshbeads, was chloromethylated to obtain an 89% yield of product. Bio-RadLaboratories, Richmond, Calif.

Anal. Found: C], 20.5, 20.7% equivalent to 5.8 mgatorn per gram EXAMPLE19 Polymer-Ligand 4 Prepared in Anhydrous Medium EXAMPLE 20Polymer-Ligand 4 Prepared in Hydrous Medium The reaction above wasrepeated, but one molar equivalent of water was added to the reactionmixture. The product weighed 5.2 g

Anal. Found: N, 7.4% equivalent to 1.76 mmoles of ligand per gram.

EXAMPLE 21 Polymer-Ligand 6 Prepared in Anhydrous Medium A 2.00 gportion of chloromethylpolystyrene (Example 18) was treated with ligand6 and sodium methoxide in anhydrous DMF as described previously toobtain 5.65 g (91%) of polymer. Anal. Found: N, 7.5, 7.8% equivalent to1.82 mmoles of ligand per gram.

EXAMPLE 22 Polymer-Ligand 6 Prepared in Hydrous Medium The aboveexperiment was repeated but with one molar equivalent of water in thereaction mixture.

Product yield was 5.16 g (79%). Anal. Found: 7.7, 7.9% equivalent to1.86 mmoles of ligand per gram.

19 EXAMPLE 23 Polymer-Ligand 1 Prepared in Anhydrous Medium The reactionof 2.00 g of chloromethylpolystyrene (Example 18) with anhydrous ligand1 was carried out as previously described. The yield of polymer was 4.03g (51%). Anal. Found: N, 6.56% equivalent to 1.56 mmoles of ligand pergram.

EXAMPLE 24 Polymer-Ligand 1 Prepared in Hydrous Medium The reaction inExample 23 above was repeated with hydrated ligand 1 to obtain 5.65 g(91%) of product. Anal. Found: 7.4, 7.1% equivalent to 1.73 mmoles ofligand per gram.

EXAMPLE 25 Polymer-Ligand 2 The reaction of 2.00 ofchloromethylpolystyrene (Example 18) with ligand 2 in anhydrous DMF gave5.12 g (78% yield) of polymer. Anal. Found: N, 10.15% equivalent to 1.82mmoles of ligand per gram.

EXAMPLE 26 Polymer-Ligand 9 EXAMPLE 27 A reaction analogous to theprevious polymer preparations was carried out with 2.00 g ofchloromethylpolystyrene beads and molar equivalents of sodium methoxideand ligand 12 to obtain 5.4 g (81% yield) ofpolymer. Anal. Found N, 9.5,9.6.

The nitrogen content was eqivalent to 1.71 mmoles of ligand per gram ofpolymer.

EXAMPLE 28 Polymer-Ligand A mixture of 3.7 g of ligand 15, 0.47 g ofsodium methoxide and 1.50 g of chloromethylpolystyrene in 50 ml ofanhydrous dimethylformamide was treated as previously described toobtain 3.48 g of product (59% yield). Anal. Found: N, 8.8, 8.4%equivalent 1.53 mmoles of ligand per gram.

EXAM PLE 29 Polymer-Ligand 17 A mixture of 3.3 g of ligand 17, 0.44 g ofsodium methoxide and 1.38 g ofchloromethylpolystyrene in 50 ml ofdimethylformamide was treated as previously described to obtain 2.96 gof polymer (52%). Anal. Found: N. 8.5. 8.6% equivalent to 1.53 mmoles ofligand per gram.

EXAMPLE 30 Polymer-Ligand 19 A mixture of 4.75 g of ligand 19, 2.0 g ofchloromethylpolystyrene and 0.63 g of sodium methoxide in 50 m1 ofdimethylformamide was treated as previously described to obtain 4.80 g(65%) of product polymer. Anal. Found: N, 8.7, 8.5 equivalent to 1.54mmoles of ligand per gram.

As previously noted the polymer-ligand compositions are useful in therecovery of metal ions. In a manner similar to that employed inconventional ion exchange, the chelating polymer-ligand compositions ofthe invention in the form of particulate solid (heads or powder) isplaced in a column and activated by equilibration with 15% sulfuricacid. The concentrated acid is then displaced by washing with 0.01Nsulfuric acid. The dilute cupric (Cu solution (concentration 50-5000 ppmCu) containing other ions (e.g. ferric (Fe"*)) is then passed throughthe column. In the case of the polymer-ligands of Example 16(C) and16(D), saturation of the chelating sites is observed as a dark green,almost black, band advancing along the column. When all the polymer issaturated, the ion solution application is stopped and the column iswashed with water; the wash and initial effluent are discarded. Themetal ions are then stripped from the column with three to five columnvolumes of 15% sulfuric acid. Acid concentrations in the range 525% maybe employed. Similarly, other strong mineral acids of equivalentconcentration may be used. The acidic extract containing the desiredcopper and/or silver ions is now suitable for electrolytic recovery.

For continuous operation the ligands are chemically attached to anendless belt such as described hereinbefore which passes sequentiallyand continuously through the mine liquor (ion solution), appropriatewash baths, and finally a stripping acid bath.

The following examples illustrate the recovery of various ions such ascopper and silver.

EXAMPLES 31-36 One gram of polymer-ligand made as described in Example16(A) was added to 10 ml of 15% sulfuric acid in a small chromatographiccolumn and that acid displaced by topwashing with 50 ml of 0.01Nsulfuric acid (dropwise). A mixture of 25 ml each of 0.05N Cu and 0.05NFe in the form of sulfates, pH 2, was passed through the column anduncoordinated interstitial ions were washed out with 25 ml of distilledwater. Coordinated ions were stripped out by washing with 25 ml of 15%sulfuric acid and the eluate diluted to ml volume with 15% sulfuric acidprior to metal ion analysis. The column was again equilibrated with0.01N sulfuric acid and another ion application, stripping cycle carriedout. After five such Cu "Fe'- runs, a mixture of 25 ml each of 0.95N Cu,Co, Ni and Ag was applied and stripped. Metal ion analyses of the acidicextracts are summarized in Table 1.

TABLE 1 Example lon Concentration in ppm CU++/FC3+ No. 100 ml Solution)Ratio (U99 F03. Ni++ Ag? 31 250 1.0 250 32 187 0.4 467 33 253 0.2 126534 177 1.1 161 35 147 0.75 196 36 103 0.2 0.2 240 21 From these data themetal ion coodinating capacity of the polymer in mg metal/g of polymeris conveniently calculated by multiplying the solution ion concentrationin ppm (parts per million) by 0.1. Thus,

from Table l the Cu" capacity of the polymer varies from about l-25 mgCu /g and the Ag capacity at least 24 mg/g depending upon the mode ofapplication of the original ion mixture.

EXAMPLES 37-39 A 2.0 g-portion of polymer-ligand (l) of Example l6(B)was used for metal ion scavenging as described under Examples 31-36.Results are summarized in Table ii and are normalized to a 1.0 g basisto simplify capacity calculation. Examples 37 and 38 were with theoriginal solutions containing only Cu and Fe and Example 39 withsolution containing also Co, Ni and Ag.

TABLE 11 Example lon Concentration in ppm Cu"/Fe No. (I00 ml Solution)Ratio C FeLH' C Ni++ Ag+ 37 2l3 0.6 370 38 384 2.5 153 39 143 0.2 0.30.5 222 7l5 EXAMPLES 40-43 A 2 g-portion of polymer ligand (1) fromExample l6(C) was used for metal ion scavenging as described above. Theresults are summarized in Table III, again normalized to 1 g of polymer.

TABLE Ill Example lon Concentration in ppm Cu*/Fe No. 100 ml Solution)Ratio C F lh C0++ Ag+ 40 58.5 0.7 84 41 87.5 l.0 88 42 1 i0 305 43 700.38 0.35 0.55 208 I84 EXAMPLE 44 ion scavenging experiments withpolymerligand (1) from Example l6(D) were carried out through 17 cycleswith Cu -Fe (or Fe) mixtures. The average capacity was 48 i 3 mg Cu /gof polymer and the average Cu /Fe' selectivity ratio was about 2000. Thelower degree of crosslinking of the chloromethylated polystyrene (1%) inthis polymer-ligand vs. the higher 2% crosslinking in the polymer-ligandof Example 16(A). (B), and C had a noticeable effect on the Cu capacityand selectivity. The capacity was increased 22 and the Cu selectivitymagnified. With a Cu 'Ag* mixture, the capacity was 37 mg Cu"*/g and 28mg Ag /g.

EXAMPLE 45 The polymer-ligand (l) of Example 44 was used for Cu recoveryfrom an actual sample otmine water obtained from the Rio Tinto mine,Mountain City. Nev. A l50-ml portion of mine water passed through theactivated polymer (2.0 g), the polymer washed with 25 ml of distilledwater and then stripped with 15% sulfuric acid (25 ml) to obtain thecomplexed metal ion extract which was diluted to [00 ml for ionanalyses. The results are summarized in Table IV.

TABLE IV Solution Description lon Content ppm C F iH Original mine water66 7.3 Eluate after passing through 0.6 7.0

column Acid extract 0.1

The polymer-ligand virtually completely removed the Cu to the almostcomplete exclusion of Fe.

EXAMPLE 46 TABLE V Solutionpescription Original solution 138 Eluateafter passing through 0.5

column (200 ml) Acid extract (200 ml) l37 The polymer-ligand (2)virtually quantitatively removed Cu from 3% nitric acid.

EXAMPLES 47-49 The polymer-ligand (2) compositions from Examples 17(A)and 17(B) were used to recover ions from mixtures (pH=2), the amount ofeach ion applied being sufficient to theoretically saturate the polymer.Results for one gram of polymer are summarized in Table VI.

TABLE VI Recovered Example Polymerlons lon concentrations in No. llgandof Applied ppm ml solution) Cu lron Co Ni Ag* 47 Ex. lS-A CO. Ni 5 67048 Ex. lX-A Cu'*Fe". 500 04 0.3 280 25 From the above table it can beseen that the tetradentheoretical capacity of each polymer. The polymercoltate polymer-ligands are very effective in selectively reumns werethen washed with water and chelated ions covering copper and nickel ionsfrom mixtures with were stripped with 15% H 80 The strip solutions wereother ions. Silver, albeit to a lesser extent, is also recovdiluted with15% H 80 to total volume of 100 ml and ered. 5 analyzed for metal ionsby atomic absorption. The results are geive in Table Vll. EXAMPLES 50'61The ion solutions (Fe column) were equimolar mix- Solutions 0.5 M inmetal ion or 0.05 M in each of sevtures of both valences Fe(ll) andFe(lll) and each eral ions as sulfates in 0.01 N H SO were applied tothe value represents an average of analyses on three sepapolymers inamount equivalent to 1 /2 times that of the 10 rate solutions; averagedeviations were about i 3-570.

TABLE VII Theoretical Capacity Expressed as Polymer-Ligand mmoles ofAccording to ligand pergn Capacity Found, mmoles/g Ex. Ex. No. L' i gar3i Sz 'u cur e 01 0 1 71 101 Fe ColIIl Ni(IIl CulIIl AMIIL G Ii 0.0010.001 0.001 0.13 0.32

ditto 1.76 0,53

ca n NH-CH2 1.82 0.67

ditto 1.86 0.69

GHQ-NH 161-011 Q 0.03 0.003 0.006 0.15 0.21

ditto 1.73 0.60

TABLE VII (continued) Theoretical Ca acit expiesseg as mmo ES 0 ggggiggig .igand per gm Capacity Found, moles/g Ex. Ex. No. Ligand Structure Fe00(11) 111(11) 00(11) Mgr) n-ca 1.79 0.0 1.38 l 1 6 1 3 0.003 0.00030.23 1.26 0.30

CH3 CH3 28 0.002 0.98 59 0.06

1.53 .002 1.00 0 CH2 nit-c31 H 0.002 0.002 0.002 0.61 0A3 N ii CH3 CH3CH H air on I -0 1.5 1.58 CH2- iii-cs CH3 CH3 various ions. for tnatparticular ion.

The results in Table VII show that the tridentate polymer-ligands ofExamples 50-55 are suitable for separating Cu(ll) from Fe(ll) andFe(lll) or isolating concentrates enriched in Cu(ll) or Ag(l) or both.

The tetradentate polymer-ligands of Examples 56- 61 permit separation ofCu(ll) from Fe(ll) and Fe(lII). The composition of Example 56 alsopermits isolation of concentrates of Cu(ll) and Ni(Il) to the exclusioneven of Ag(l). Appropriate substitution such as in Example 58 permitsisolation ofCu(ll) and Ag(l) concentrates.

Use ofdifferent polymers in series permits separation of each of theions Ni(ll), Cu(ll) and Ag(l) individually.

The embodiment of the invention in which an exclu- Analyses fo more thanone metal ion in any given row means that a mixture of ions was applied,thus chelation is competitive and the results measure the selectivity ofchelation among A single value in any given row measures the absolutecapacity of the resin sive property or privilege is claimed are definedas fol- 60 gram of polymer, the ligand having tne formula 27 t 28wherein 8. A polymer-ligand according to claim 1 in which R is H oralkyl of 1-3 carbon atoms; the ligand has the formula X and Xindependently are NH, O or S: Y is -Z Z z and t 9. A polymer-ligandaccording to claim 1 in which Y is the ligand has the formula N; R H CNHNHCH a. 2 2 in which 2 is O-, -S, S(CH O(CH NH, or NH(CH where n l tol0; "0 Q is N; and 2S Q is NH, O, or S; with the priviso that at leastthree of X, X, Q and O f A polymer'hgand accordmg to clam l m whlch arenitrogen; the ligand has the formula said ligand being attached to themethylene carbon by the indicated valence bond and attached to thepolymer through the Z group. 2. A polymer-ligand according to claim 1 inwhich the said indicated valence bond is ortho to the Q or Q H CNH NHGH2atom. Q 2

3. A polymer-ligand according to claim 1 in which X b and X are each N.N N

4. A polymer-ligand according to claim 1 in which the polymer ispolystyrene.

5. A polymer-ligand according to claim 1 in which CH the polymer iscrosslinked polystyrene. 3

6. A polymer-ligand according to claim 1 in which 1 H d h h f l 11. Apolymer-ligand according to claim I in which the ligand has the formulaNH H2 6 l 12. A polymer-ligand according to claim I in which the ligandhas the formula 7. A polymer-ligand according to claim 1 in which H Hthe ligand has the formula 3 3 0 H NH NHCH 2 H 2 6s N 13. Apolymer-ligand according to claim 1 in which the ligand has the formula14. A polymer-ligand according to claim 1 in which the ligand has theformula CH3 H UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 5,873,668

DATED 1 March 25, 1975 N N O (S) Lester Russell Melby It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

C01. 27, line 28 after "said" insert Y group of the Signed and sealedthis 24th day of June 1975.

Attest:

C. IZARSZIALL DAMN RUTH C. MASON Commissioner of Patents attesting,Officer and Trademarks

1. A POLYMER-LIGAND COMPRISING A HIGH MOLECULAR WEIGHT WATER INSOLUBLE POLYMER CONTAINING ABOUT 0.3 TO ABOUT 2 MILLIMOLES OF A COVALENTLY BONDED LIGAND PER GRAM OF POLYMER, THE LIGAND HAVING THE FORMULA
 2. A polymer-ligand according to claim 1 in which the said indicated valence bond is ortho to the Q or Q'' atom.
 3. A polymer-ligand according to claim 1 in which X and X'' are each N.
 4. A polymer-ligand according to claim 1 in which the polymer is polystyrene.
 5. A polymer-ligand according to claim 1 in which the polymer is crosslinked polystyrene.
 6. A polymer-ligand according to claim 1 in which the ligand has the formula
 7. A polymer-ligand according to claim 1 in which the ligand has the formula
 8. A polymer-ligand according to claim 1 in which the ligand has the formula
 9. A polymer-ligand according to claim 1 in which the ligand has the formula
 10. A polymer-ligand according to claim 1 in which the ligand has the formula
 11. A polymer-ligand according to claim 1 in which the ligand has the formula
 12. A polymer-ligand according to claim 1 in which the ligand has the formula
 13. A polymer-ligand according to claim 1 in which the ligand has the formula
 14. A polymer-ligand according to claim 1 in which the ligand has the formula
 15. The process of removing cupric or argentous ions from their aqueous solution which also contains other metal ions, which comprises contacting said aqueous solution with a polymer-ligand according to claim 1 to selectively bind cupric or argentous ions to the polymer-ligand, removing the polymer-ligand containing the bound ions, and recovering the ions from the polymer-ligand.
 16. The process of claim 15 in which sulfuric acid of 1-25% strength is used to recover the ions from the polymer-ligand. 